The Nantucket Shoals Flux Experiment (NSFE79). Part II: The Structure and Variability of Across-Shelf Pressure Gradients

The Nantucket Shoals Flux Experiment (NSFE) was a collaborative effort to measure the alongshelf transport of mass, heat, salt and nutrients from March 1979 through April 1980 with a dense army consisting of moored current, temperature and bottom pressure instruments in an across-shelf and upper-slope transect south of Nantucket Island. The pressure component of that experiment is described here. Bottom pressure recorders were deployed at stations N1 (46 m), N2 (66 m), N4 (105 m), and N5 (196 m) during two half-year periods. spring–summer 1979 (SUMMER) and fall–winter 1979/80 (WINTER). A synthetic subsurface pressure (SSP) record was formed from atmospheric pressure and sea level observations at Nantucket Island. The low-pass filtered (periods > 36 h) or subtidal pressures were used for the subsequent analysis. It was found that Nantucket SSP and BP are very nearly equivalent for fluctuation periods less than about 50 days if steric changes in sea level, due to density changes above the seasonal ...